The present invention relates to the exhaust gas emitted from a turbomachine, and more particularly to a system and method of utilizing a turbomachine as a prime mover of the exhaust gas recirculated within an EGR system.
There is a growing concern over the long-term effects of Nitrogen Oxides (hereinafter NOx) and Carbon Dioxide (hereinafter “CO2”) and Sulfur Oxides (SOx) emissions on the environment. The allowable levels of emissions that may be emitted by a turbomachine, such as a gas turbine, are heavily regulated. Operators of turbomachines desire methods of reducing the levels of NOx, CO2 and SOx emitted.
Significant amounts of condensable vapors exist in the exhaust gas stream. These vapors usually contain a variety of constituents such as water, acids, aldehydes, hydrocarbons, sulfur oxides, and chlorine compounds. Left untreated, these constituents will accelerate corrosion and fouling of the internal components if allowed to enter the turbomachine.
Exhaust gas recirculation (EGR) generally involves recirculating a portion of the emitted exhaust through an inlet portion of the turbomachine. The exhaust is then mixed with the incoming airflow prior to combustion. The EGR process facilitates the removal and sequestration of concentrated CO2, and may also reduce the NOx and SOx emission levels.
There are a few concerns with the currently known EGR systems. Some EGR systems incorporate a fan or blower to drive the recirculated exhaust throughout the EGR system. The fan or blower requires additional costs, maintenance, generates noise, and will require damping.
For the foregoing reasons, there is a need for a system and method of driving the recirculated exhaust throughout an EGR system. The system and method should not require a fan or blower to drive the exhaust throughout the EGR system.